Crossflow radiators



Sept. 27, 19 P. K. BEATENBOUGH ETAL 3,

CROSSFLOW RADIATORS Filed April 9, 1963 INVENTORS United States Patent3,275,070 CROSSFLOW RADIATORS Paul K. Beatenbough, Medina, and Robert W.Bishop,

Lockport, N.Y., assignors to General Motors Corporation, Detroit, Mich.,a corporationof Delaware Filed Apr. 9, 1963, Ser. No. 271,743 2 Claims.(Cl. 165111) This invention refers to heat exchangers and moreparticularly to a radiator of the crossfiow type adapted to serve aninternal combustion engine, and also to a combination of such a radiatorwith a liquid cooled internal combustion engine.

Crossflow radiators have been used for many years.

One reason for the continued efforts to use them is that they permitlower installation in vehicles as compared with the more conventionaldownfiow type. Heretofore, however, such radiators have been generallyunacceptable. Expensive provisions for air removal and supplementarycoolant reserve tanks have been employed with crossfiow radiators toinsure that the radiator tube outlets are maintained full of enginecoolant at all times. A comm-on and basic difficulty has been that, ascoolant is heated, it expands and some of it is lost through an overflowport. As the coolant subsequently cools and contracts, air is drawn intothe system through the overflow port or a vacuum valve. If the air isnot collected at the overflow zone, the cooling system will act like apump to exhaust coolant with each heating and cooling cycle. In theteachings of the United States patents to 'Muir, 1,860,783, granted May31, 1932 and 1,576,756, granted March 16, 1926, air vents areprovided atthe tops of outlet header tanks where air gathers but users of suchradiators continually replaced coolant in vain attempts to maintain toptanks full. Providing top header tanks eliminated a main advantage(lower installation) of crossflow radiators and in the patentedstructuresreferred to, coolant loss is great because of the frequentrefills referred to.

It has now been discovered that top or supplementary coolant reservetanks are not necessary while the flow of coolant is maintained throughall tubes in a crossflow radiator capable of stable and efficientperformancei.e.-an operation without the operator feeling it necessaryoften to check the coolant level.

To this end, an object of the present invention is to provide animproved crossflow radiator capable of eflicient performance without theuse of a top or added reserve supply tank. Another object is to providean improved combination of an engine and a crossflow radiator.

A feature of the present invention is a crossfiow radiator comprising acore with tubes connecting two side tanks, one of the latter beingadapted to serve as a coolant inlet tank for receiving coolant and theother having means for removing air and being adapted to serve as acoolant outlet tank, the air removing means being above the outlet andthe coolant capacity of the radiator being suflicient to include anecessary reserve supply of coolant in the absence of a top orsupplementary tank. Another feature is a combination of an engine and acrossflow radiator in which no reserve radiator tank in the form of atop, side or detached tank is employed.

These and other important features of the invention will now bedescribed in detail in the specification and then pointed out moreparticularly in the appended claims.

In the drawings:

FIGURE 1 shows a front elevation of an automobile engine with a directconnection to a radiator being shown diagrammatically, the radiatorbeing shown in perspective and the combination representing oneembodiment of the present invention;

3,275,070 Patented Sept. 27, 1966 FIGURE 2 is an elevation view of theradiator shown in FIGURE 1 anddrawn to a larger scale'an'd with aportion broken away better to illustrate the invention;

FIGURE 3 is a sectional view, drawn to a larger scale, looking in thedirection of the arrows 3-3 in FIGURE 2; and

FIGURE 4 is a sectional view drawn-to the same Scale as FIGURE 3 andlookingin'the direction of the arrows 44 in FIGURE 2. v

In the drawings, a typical automobile V-8 engine is illustrated at 10.This engine is provided with a'coolant pump 12 and a pump outlet flowconnection 14 as well as a coolant jacket inlet connection 16. Acrossflow radiator is depicted at 18. This radiator has two side tanksaninlet tank 20 and an outlet tank 22. These two tanks are provided withan inlet 24 and an outlet 26 respectively. The inlet 24 is preferablybut not necessarily located in the top portion of the inlet tank 20.'The outlet 26 is preferably located in a low portion of the outlet tank22 and is necessarily located below a vent connection 27 whichcommunicates with a top portion of the outlet tank 22 as will furtherappear. The pump coolant outlet 14 and the radiatorinlet 24 aredirectlyconnected by a conduit diagrammatically represented .by a dottedline 28. The radiator outlet 26 and the engine jacket coolant inlet 16are directly connected by a conduit diagrammatically represented by adotted line 30. It will be noted that there are no supplementary tanksutilized in the cooling system of the illustrated combination of theengine 10 and the radiator 18.

In FIGURE 3, it is seen that horizontally extending tubes 32 of theradiator core 33 have ends passing through a tube sheet 34 and incommunication with the inlet tank 20. Air centers 36 in'the form ofcorrugated thin sheets of metal are utilized in a conventional mannerbetween sets of adjacent rows of tubes 32 to enhance heat exchangecharacteristics of the radiator as is well known in the art. It will bealso understood that the tubes 32 communicate with the outlet tank 22 inthe same manner as depicted with relation to the inlet tank 20.

FIGURE 4 illustrates the relation of a radiator stiffening or framestructure 38 with respect to the core 33 with its air centers 36 andmutiple flat tubes 32.

On the top of the outlet tank 22 is located a conventional pres-sure cap40 which seats on a shoulder 42 with-in a radiator filler neck 44. Itwill be understood that when a predetermined pressure is exceeded in theradiator or cooling system, a spring of the pressure cap will compressand the radiator will be vented by way of the vent 27. A cap suitablefor use in regulating the pressure is disclosed in the United StatesPatent 2,865,531 granted December 23, 1958 in the names of J. R. S.Gorst and S. W. Kemp.

In operation, engine coolant is forced by the pump 12 to flow throughthe conduit 28 and into the inlet tank 20. The coolant then flowshorizontally through all the tubes 32 and is cooled by air flowingthrough the core 33 and by the fins or air centers 36. The air-cooledcoolant then flows into the outlet tank 22 which defines an integrated,substantially unrestricted, or free flow zone 50 served by the outlet 26and venting means generally indicated at 52 and including the closure 40and the vent pipe 27. The air-coolant interface in the outlet tanksmoves up and down in operation but this in no way interferes with theflow of coolant through the upper horizontal tubes 32. The zone 50 issized to fit other proportions and dimensions of a given cooling systemto permit the air-coolant interface to form. In a given design, if theflow rate were increased unduly, a condition would be reached at whichthe flow velocity in the zone 50 will sweep air along with it andthereby prevent air separationi.e.the flow velocity the vent.

in a given installation must be low enough to permit entrained air toseparate for venting and in the zone having The de-aerated coolant thenreturns directly to the jacket of the engine '10 by way of the conduit30.

In the operation as above outlined, the cooling system depends upon pumppressure to force, coolant through the radiator core 33 against the flowresistance of the latter. The cooling system is designed so that pumpflow rate exceeds the gravity flow-rate through the radiator (that is,the flow rate is such that the inlet tank 20 is maintained full ofWater).- If this condition is met then flow occurs in only onehorizontal direction through the radiator'and through all radiator tubes32 without regard to the location of the air-water interface in theoutlet tank 22. The

,size and shape of the inlettank 20 are immaterial considerationsprovided that the tank 20 is not so small as to throttle pump flow rate;to anextent thatIthe latter falls'below the radiator gravity flow rate.

proper conditions described, air cannot separate in the in-- let tank 20since it will be swept therefrom and by way of the radiator core tubesto the separation zone 50. If

' the pump flow rate is permitted to fall below the radiator gravityflow rate, the system will continue to separate some air in the outlettank but some air will also collect in the upper portion of the inlettank and coolant flow will cease through those radiator tubes which areabove the air-coolant interface in the inlet tank. With proper pumppressure and no undue throttling of flow between the pump '12 and thecore 33, the system and radiator Will operate in a stable and eflicientfashion.

We claim:

1. A crossfiow radiator comprising only two elongated Under the andsufficiently large relative to the coolant flow rate through the saidtubes to permit air to separate from said coolant upon the latterdischarging from said tubes into. said outlet tank, and the path forfluid defined by said two tanks and tubes being in only one horizontaldirection.

2. A combination of an internal combustion engine coolant jacket with anengine coolant pump and a crossflow radiator forming a closedcirculatory system, said radiator being an integral unit of only twotanks and a core with horizontally extending tubes, said tanksbeingseparated by a space occupied by said core and having verticallyelongated facing sides serving as tube sheets for said tubes, one ofsaid tanks having a coolant inlet, conduit means in said system forminga direct connection between said jacket and pump to said coolant inlet,said conduit means defining afiow path of substantially constant crosssectionto give asubstantially uniform flow rate along its length, theother of said tanks having a top portion defining a zone in freecommunication with said tubes and having a sufficientlylarge volumerelative. to the flow rate through the said tubes to permit'air toseparate from coolant discharged by said. tubes, saidother tank having acoolant outlet located below .said

zone and connected to, other conduit means forming part of said system,a pressure actuated air vent connected to said zone, and the path forcoolant flow defined by said radiator being in only one horizontaldirection.

References Cited by the Examiner ROBERT A. OLEARY, Primary Examiner.

CHARLES SUKALO, JAMES W. WESTHAVER,

Examiners.

A. W. DAVIS, Assistant Examiner.

1. A CROSSFLOW RADIATOR COMPRISING ONLY TWO ELONGATED TANKS EACH HAVINGA VERTICAL SIDE, THE SAID TANKS BEING AN INLET TANK AND AN OUTLET TANK,A CORE WITH TUBES EXTENDING HORIZONTALLY AND CONNECTING THE VERTICALSIDES OF SAID TANKS TO FORM FLOW PASSAGES LEADING FROM SAID INLET TANKTO SAID OUTLET TANK, SAID INLET TANK HAVING A COOLANT INLET, SAID OUTLETTANK HAVING A COOLANT OUTLET, A PRESSURE ACTUATED AIR VENT CONNECTED TOATMOSPHERE AND LOCATED AT THE TOP PORTION OF SAID OUTLET TANK IN FREECOMMUNICATION WITH TUBES OF SAID CORE, THE HORIZONTAL CROSS SECTIONALAREA WITHIN THE SAID TOP PORTION OF SAID OUTLET TANK BEING CLEAR ANDSUFFICIENTLY LARGE RELATIVE TO THE COOLANT FLOW RATE THROUGH THE SAIDTUBES TO PERMIT AIR TO SEPARATE FROM SAID COOLANT UPON THE LATTERDISCHARGING FROM SAID TUBES INTO SAID OUTLET TANK, AND THE PATH FORFLUID DEFINED BY SAID TWO TANKS AND TUBES BEING IN ONLY ONE HORIZONTALDIRECTION.